Compressor



Nov. 6, 1962 COMPRESSOR United States Patent Oflfice 3,062,434 Patented Nov. 6, 1962 3,062,434 COMPRESSOR John R. Elwell, Dearborn, Mich., assignor to Ford Motor Company, Deal-born, Mich., a corporation of Delaware Filed Sept. 30, 1960, Ser. No. 59,643 5 Claims. (Cl. 230-51) This invention relates to air conditioning system compressors and more particularly to an axial piston refrigerant compressor.

Refrigerant compressors for motor vehicle air conditionng systems are conventionally driven from the vehicle engine by means of a belt drive power take-off. The use of such a drive dictates that the driving and driven shafts be parallel to avoid the adverse effects of sharp bends in the belt, therefore, the compressor shaft must be horizontally disposed. Operation of axial piston compressors in a horizontal position gives rise to several undesirable conditions. The lubricating oil, because of leakage, has a tendency to mix with the fluid being compressed and a loss of efi'iciency of the system and eventual malfunctioning of the compressor results. Churning of the lubricating oil in the compressor bases also occurs with attendant inadequate lubrication of the moving parts.

It is an object of this invention to provide a compressor assembly having a plurality of coaxially arranged cylinder blocks.

A further object of this invention is to provide acompressor Which can be operated in a substantially vertical position and does not depend upon a belt drive power take-off for its driving power. It is a still further object to provide a compressor which is compact and reliable for long duration operation.

More particularly, this invention provides an axial piston compressor that is driven by a fluid motor the cylinder block of which is located in coaxial relationship with the cylinder block of the compressor. Further object and advantages of this invention willy become more apparent as this description proceeds, particularly when considered in connection with the accompanying drawings in which:

FIGURE 1 is a vertical sectional view of the invention and,

v FIGURE 2 is a sectional view taken along line 2-2 of FIGURE l. i

Referring now to the drawings, and more particularly to FlGURE l, there is shown generally at 11 a compressor suitable for use in an a-ir conditioning system of a motor vehicle. The compressor includes a casing 12 having a base 13 provided with holes 14 to facilitate installation of the compressor. The compressor assembly is preferably mounted with its longitudinal axis in a substantially vertical position.

Contained within the casing 12 are a pair of radially spaced coaxial cylinder blocks 15 and 16. The cylinder block 15 is fixed against rotation relative to the casing 12 and ha-s a plurality of cylinder bores 17 formed therein. As can be seen, the cylinder bores 17 are equally spaced from the longitudinal axis common to cylinder blocks 15 and 16. Compressor pistons 18 are slidably mounted in the cylinder bores 17 and are connected by means of connecting rods 19 to a wobble plate 21. Connecting rods 19 are spherically formed at each end 22 to form a ball and socket connection with pistons 18 and wobble plate 21. Wobble plate 21 is held from rotation by means of a ball 23 which acts in groove 24 formed in the wall of a swash plate casing 25. The ball 23 is supported by a pin 26 Secured to wobble plate 21. Wobble plate 21 is driven by a swash plate 27 which is, in turn, driven by shaft 28 to which it is keyed as at 29. Shaft 28 is coaxial with the longitudinal axis of cylinder blocks 15 and 16. Rotation of the shaft 28 causes reciprocation of pistons 18 in the known manner.

As the pistons 18 move upward in the cylinder bores 17, a partial vacuum is created in swash plate casing 25. The refrigerant to be compressed is, thus, drawn into the swash plate casing 25 through inlet connection 31 which is Secured to compressor casing 12. Pistons 18 are formed with passages 32. The refrigerant is admitted to the cylinders 17 through these passages by the action of reed valves 33 which open as the pistons 18 move downward and close as the pistons 18 move upward in the cylinder bores 17 to compress the refrigerant. The compressed refrigerant is discharged from the cylinder bores 17 through plate valves 34 located in the top of the cylinder walls adjacent cylinder head 35. The plate valves are maintained in the seated position by compression spring-s 36. When the refrigerant is compressed to the desired pressure, which may be controlled by the rate of Springs 36, plate valves 34 will open and the compressed refrigerant is discharged through the ports 37 formed in the cylinder head 35.

The compressor is driven by means of an axial piston fluid motor, indicated generally at 48. The fluid motor 48 is contained entirely within the compressor cylinder block 15 and includes the rotatable motor cylinder block 16. Cylinder block 16 has formed therein aplurality of cylinder bores 49 in which the motor pistons 51 are slidably supported for reciprocation relative thereto. The motor cylinder bores 49 are equally spaced from the longitudinal axis of cylinder blocks 15 and 16 at a lesser radial distance than the compressor cylinder bores 17. Pistons 51 are formed with sockets at their lower end which receive balls 52 of hydrostatic slippers 53 to form a ball joint connection therewith. The slippers 53 bear against the inclinedthrust plate 54. Thrust plate 54 is supported in compressor cylinder block 15 by means of the Snap ring SS and is held against rotation relative to cylinder block 15 by the action of a-n inclined spacer 56. The spacer 56 is held against rotation relative to the cylinder block 15 by pin 57.

' Fluid under pressure may be supplied to the fluid motor 48 from any suitable source. The power steering pump of the motor vehicle could serve as such a source. Fluid under pressure is admitted to the fluid motor 48 through pressure inlets 58 formed in the extension 59 of compression cylinder block 15. Fluid exhaust ports 61 are formed in the extension 58 through which spent fluid is exhausted from the motor 48. Inlet of the fluid to the motor cylinders is controlled by plate valve 62 of a known type. A compression spring 63 acting on the motor cylinder block 16 through thrust plate 64 serves to maintain an initial seat between the plate valve 62 and the adjacent surfaces of compressor cylinder block extension 59 and motor cylinder block 16. Once the motor is in operation under fluid pressure, such pressure serves to keep this valve seated. Upon admission of high pressure fluid to the cylinder bores 49, the pistons 51 are forced downward and the reaction of hydrostatic slippers 53 against the stationary inclined thrust plate 54 causes the cylinder block and associated assembly to rov tate.

A seal 6-5 of carbon or other suitable material surrounds shaft 28 to prevent mixing of the refrigerant and the fluid used to power fluid motor 48. This seal is maintained in position by the action of compression spring 66. To prevent build up of fluid pressure in the lower portion of the motor 48 and possible resulting leakage into the compressor section through Seal 65, a motor drain is provided. This drain consists of a hole 67 bored through thrust plate 54 which hole cooperates with a similar hole (not shown) bored in cylinder block 15. Thus, any fluid which escapes from the hydrostatic slippers 53 is allowed to drain off before pressure on the seal 65 from above can accumulate.

The rotary movement of motor cylinder block 16 is transmitted to shaft 28 by means of spline connection 68 between these elements. Shaft 28 is mounted for rotation by bearing 69 contained in cylinder block extension 59 and hearing 71 carried in thrust plate 54. At its lower end, shaft 28 and swash plate 27, which it drives, are supported for rotation by means of the plain bearing surface 72 formed in the swash plate casing 25.

The moving parts of the compressor portion of the assembly described are lubricated by means of a lubricating pump, generally indicated at 38. Any suitable type of lubricating pump may be used although an eccentrically driven, single piston pump is preferred. This type of pump is Well known in the art. The lubricating pump discharges through a passage 39 formed in the swash plate 27 and lubricates the connecting rod ball sockets by means of passages 41 formed in the wobble plate 21. As may be seen, the connecting rods 19 are hollow and formed With lubricating passages 42 that allow the lubricant to reach the ball joints located at the pistons. An oil sump 43 is provided in compressor casing 12 below swash plate casing 25. The pump 38 draws from this reservoir through the inlet pipe 44 and forces oil to the moving parts through the before mentioned passages. The circulated lubricating oil returns to the sump through drain holes 45 formed in the swash plate casing 25. Oil may be added to the sump 43 through filler pipe 46 provided with cap 47.

It can thus be seen that a compact motor driven compressor is provided in which the driving motor is located within the cylinder block of the compressor and the use of be'lt drives is eliminated.

' It will be understood that the invention is not to be limited to the exact construction shown and described but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.

I claim:

1. A fluid driven compressor comprising a fiXed cylindrical casing, a first cylinder block secured to said casing and having a plurality of spaced cylinder bores formed therein, a second cylinder block rotatably received in said casing and having a plurality of cylinder bores formed therein, a first set of pistons reciprocally received in the cylinder bores of said first cylinder block, a second set of pistons reciprocally received in the cylinder bores of said second cylinder block, motion translating means operative to translate rotary motion of said second cylinder block into reciprocatory motion of said first set of pistons, first valve means operable to sequentially admit and discharge fluid to and from said first cylinder block, second valve means operable to sequentially admit and discharge fluid to and from said second cylinder block, a source of fluid under pressure, and fluid conduit means interconnecting said source of fluid under pressure and one of said valve means to drive the compressor.

2. A fluid driven compressor comprising a first cylinder block having a plurality of spaced cylinder bores formed therein, a first set of pistons slidably received in said cylinder bores for reciprocation relative thereto, a second cylinder block rotatable with respect to said first cylinder block, said second cylinder block having a plurality of spaced cylinder bores formed therein, a second set of pistons slidably received in said cylinder bores of said second cylinder block for reciprocation relative thereto, a source of fluid under pressure, valve means operable to sequentially admit and discharge fluid under pressure to and from said second cylinder block, conduit means interconnecting said source of fluid under pressure and said valve means to cause said second set of pistons to reciprocate relative to their respective cylinder bores and cause said second cylinder block to rotate,

means fixing said first cylinder block against rotation, valve means operable to sequentially admit and discharge fluid from said first cylinder block, and means operative to translate rotary motion of said second cylinder block into reciprocatory motion of said first set of pistons Whereby said first set of pistons may act as a fluid compressor means.

3. A fluid driven compressor comprising a cylindrical casing, shaft means rotatably journaled within said casing on the longitudinal axis thereof, first and second cylinder blocks concentrically positioned within said casing, each of said cylinder blocks being provided With a pluralty of spaced cylinder bores, a first set of pistons slidably received in the cylinder bores of said first cylinder block for reciprocation relative thereto, a second set of pistons slidably received in the cylinder bores of said second cylinder block for reciprocation relative thereto, means fixing said first cylinder block relative to said casing, means operatively connecting said second cylinder block and said shaft for rotation therewith, motion translating means translating rotary motion of said shaft into reciprocatory motion of said first set of pistons, a source of fluid under pressure, valve means operable to sequentially admit and discharge fluid under pressure to and from said second cylinder block, and fluid conduit means interconnecting said source of fluid under pressure and said valve means to cause said second set of pistons to reciprocate relative to their respective cylinder bores thereby causing said second cylinder block to rotate and said first set of pistons to reciprocate in their respective cylinder bores.

4. A fluid driven compressor comprising a cylindrical casing, a vertically disposed shaft rotatably journaled within said casing on the longitudinal axis thereof, first and second cylinder blocks concentrically positioned within said casing, each of said cylinder blocks being provided with a plurality of cylinder bores, a first set of pistons slidably received in the cylinder bores of said first cylinder block for reciprocation relative thereto, a second set of pistons slidably received in the cylinder bores of said second cylinder block for reciprocation relative thereto, means fixing said first cylinder block relative to said casing, a source of fluid under pressure, valve means operable to sequentially admit and discharge fluid under pressure to and from said second cylinder block, conduit means interconnecting said source of fluid under pressure and said valve means to cause said second set of pistons to reciprocate relative to said second cylinder block and cause said second cylinder block to rotate, means operatively connecting said second cylinder block and said shaft for rotation therewith, and motion translation means translating rotary motion of said shaft into reciprocatory motion into said first set of pistons whereby the latter may act as a fluid compressor means.

5.A fluid driven compressor comprising a fixed cylindrical casing, a vertically disposed shaft rotatably journaled within said casing on the longitudinal axis thereof, first and second cylinder blocks concentrically positioned within said casing, each of said cylinder blocks being provided with a plurality of cylinder bores, a first set of pistons slidably received in the cylinder bores of said first cylinder block for reciprocation relative thereto, a second set of pistons received in the cylinder bores of said second cylinder block for reciprocation relative thereto, means fixing said first cylinder block relative to said casing, a source of fluid under pressure, valve means operable to sequentially admit and discharge fluid under pressure to and from said second cylinder block, conduit means interconnecting said source of fluid under pressure and said valve means to cause said second set of pistons to reciprocate relative to said second cylinder block and cause said second cylinder block to rotate, means operatively connecting said second cylinder block and said shaft for rotation therewith, valve means operable to sequentially admit and discharge fluid to and from said first cylinder block, and motion translation means translating rotary motion of said shaft into reciprocatory motion into said first set of pistons whereby the latter may act as a fluid Compressor means.

References Cited in the file of this patent UNITED STATES PATENTS 1,840,865 Rayburn et al. Jan. 12, 1932 2,114,076 Golz Apr. 12, 1938 2,784,671 Wilcox Mar. 12, 1957 

